To determine the number of tickets that Ric sold, subtract from the total tickets sold the sum of the number of tickets sold by Alex and Ian. This is mathematically shown as,
tickets (Ric) = tickets (total) - (tickets (Alex) + tickets (Ian))
tickets (Ric) = 48 - (11 + 18) = 19
Hence, Ric sold 19 tickets for the fundraising.
The chance of you selecting one randomly is 4/56, which simplifies to 1/14.
It should be -3x but i could be wrong
